// the same as PTA_wengkai_2/7-1.c

#include<stdio.h>

double fact(int n);
int main()
{
    int m, n;
    scanf("%d %d", &m, &n);
    double C = fact(n) / (fact(m) * fact(n - m));
    printf("result = %d", (int)C);

    return 0;
}

double fact(int n)
{
    if (n == 0 || n == 1)
    {
        return 1;
    }
    else
    {
        return n * fact(n - 1);
    }
    
}